Laboratory Diagnosis by Langmuir Probe for Plasma Parameters Generated around the Spacecraft Model

Abstract

       The problem of interruption of communication between the spacecraft and the ground station due to the plasma formed around the spacecraft is one of the important and dangerous problems facing spacecraft during their return to the Earth’s gaseous atmosphere. The present work focused on diagnosing the plasma parameters generated around a laboratory spacecraft model. A vacuum system was used to produce plasma under a working pressure of 0.1 mbar. The spacecraft model was placed inside this plasma between the cathode and the anode, and a strong magnetic field was used to confine the plasma around the model. A single Langmuir probe was used to calculate the electron temperature, electron density, Debye radius, and plasma frequency. Plasma frequency is an important and decisive factor for selecting the frequencies used in communication between the spacecraft and the ground station. The values ​​of these plasma parameters were obtained with the discharge power varying from 20 watts to 100 watts for the system used in the practical experiment. Electron Temperature values ​​ranged between values 0.389-0.982 eV, electron density, between values 4.8x10¹³-2x10¹⁴ cm^-3 and plasma frequency values ​​ranged between 6.23x10⁷-1.2x10⁸ Hz.